The View Configuration Properties, also called wrapper source
configuration, allow indicating specific characteristics of the
underlying data sources such as their distributed transaction support
capacity or whether insert operations are allowed.

This section lists the configurable properties of a base view, depending
on the type of data source they have come from.

Usually, users do not need to edit these properties since
Virtual DataPort automatically uses suitable configurations for most
common data sources.

To configure the properties of a base view, open the Options dialog
of the view and then, click on the Search methods tab. In this
dialog, underneath the search methods (using the scroll bar where
necessary), click Wrapper Source Configuration. The configurable
properties are the following:

Allow insert (configurable in JDBC and ODBC base views): If yes,
it indicates that the underlying data source supports INSERT
operations.
If no, the INSERT operations over this view will be rejected.

Allow delete (configurable in JDBC and ODBC base views): If yes,
it indicates that the underlying data source supports DELETE
operations.
If no, the DELETE operations over this view will be rejected.

Allow update (configurable in JDBC and ODBC base views): If yes,
it indicates that the underlying data source supports UPDATE
operations.
If no, the UPDATE operations over this view will be rejected.

Delegate SQL sentence as subquery (configurable in JDBC base
views): If yes (default value) and the base view has been created
from a SQL query, at runtime, Virtual DataPort will be able to
delegate the SQL query of the base view as a subquery in the FROM
clause. This increases the number of operations that can be delegated
to the database.

For example, let us say that we have created a JDBC base view called
customer_info from the following SQL query:

If this property is set to no, Virtual DataPort executes the SQL
query of the view customer_info in the database and then, over the
results obtained from the database, it executes the GROUPBY
operation and the COUNT function.

If this property is set to yes, the entire query can be delegated to
the database by putting the SQL query of the base view in a subquery:

In this scenario, Virtual DataPort does not have to process the
GROUPBY and the COUNT and the amount of traffic between the
database and Virtual DataPort is diminished.

Although this property is set to “yes”, the entire query cannot always
be executed in the database. This happens in the following scenarios:

The query executed in Virtual DataPort involves functions not supported
by the database.

A SQL statement is not delegated as a subquery if it contains the
token @WHEREEXPRESSION.

A nested join cannot be delegated to the database if the following
conditions are met:

The base view created from a SQL query, is used in the right side of
the join.

The SQL query of the base view has interpolation variables.

And, the values of these variables are obtained from the query of the
left side of the join.

Note

Set this property to no if the SQL query cannot be delegated
as a subquery. For example, if the query uses “common table
expressions”. E.g.

WITHcteAS(SELECT*FROMVIEW)SELECT*FROMcte

Supports distributed transactions (configurable in JDBC and ODBC
base views): If yes, it indicates that the underlying data source can
take part in XA distributed transactions.

Fields by which the data is sorted in the source (configurable in
all the base views, except Custom ones): This property indicates the
fields by which the data is ordered. The syntax of this property is
the following:
<fieldname>{ASC|DESC}[,<fieldname>{ASC|DESC}]*

For example,
field1DESC

E.g., let us say that we have a Web service base view with the fields
F1 and F2. We know that the results of querying the Web service
are ordered in ascendant order by the field F1 and then, by
descendant order by the field F2. By setting this property to
F1ASC,F2DESC, we are telling Virtual DataPort the order of the
result and it may be able to perform certain optimizations such as
selecting a most efficient join algorithm. See more about this in the
section Merge Join.

Delegate operators list (configurable in Multidimensional base views
that connect to SAP and Web service base views): This property
determines the list of operators that can be delegated to the data
source. This list allows Virtual DataPort to optimize the query plan by
delegating part of the processing to the source. While the Server
carries out this action automatically on relational databases, other
types of sources do not provide this information about their metadata.

To configure the properties of these base views, open the base view by
double-clicking on it in the Server Explorer and then click Options.
In this dialog, underneath the search methods (using the scroll bar
where necessary), click on Wrapper Source Configuration to open the
property configuration screen.

The configuration properties of Google base views are “Site
Collections”, “Client”, “Languages” and “Number of Key match”. See
section Google Search Sources for more information about these
properties.